The need for keying interconnectable components is well known. There is a special need in the electrical/electronic area to provide for the keyed interconnection of one component to another. These components may be connectors which terminate electrical or fiber optic cable which when connected provide for transmission of signals therebetween. The connector art has seen a wide variety of techniques for matching together connectors which are to be mated to one another. These techniques include, for example, interfitting parts such as matching projections and recesses which permit a matched set of components to be interconnected while preventing the interconnection of similar connectors which are not intended to be interconnected. Many connectors include these mating projections and recesses formed integrally with the connector housings at various preselected positions. Thus, one particular type of housing would be manufactured for interconnection with another connector specifically designed for interconnection therewith.
An advance in keyed connectors is achieved by providing connectors manufactured to accommodate separate projections at various locations thereon. Thus, after manufacture, each connector could be separately keyed to mate with differently keyed mating connectors. While the latter technique improves upon the former in that it reduces the necessity of manufacturing individually keyed connectors, removable keys of this type have several limitations. Numerous keys must be formed having different shapes and sizes to distinguish one key from another. Alternatively, numerous key positions must be provided on the connector to provide the same distinguishing characteristics. In addition, removable keys typically provide no function to the connector structure other then providing a means for keyed interconnection. Therefore the keys are often misplaced or not used thereby rendering the intended keying function useless.
It is therefore desirable to provide a connector structure having a single key which provides plural mutually exclusive key positions. It is also desirable to provide a keying device for a connector structure whereby the key is necessary for proper operation of the connector structure thereby avoiding inadvertent absence of the key in the connector structure.